linux-kernel - Re: Re: [PATCH] Input: omap-keypad - fix runtime pm imbalance on error

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Date:   Thu, 21 May 2020 13:19:01 +0800 (GMT+08:00)
From:   dinghao.liu@....edu.cn
To:     "Dmitry Torokhov" <dmitry.torokhov@...il.com>
Cc:     "Rafael J. Wysocki" <rafael@...nel.org>,
        "Kangjie Lu" <kjlu@....edu>,
        "Richard Fontana" <rfontana@...hat.com>,
        "Allison Randal" <allison@...utok.net>,
        "Thomas Gleixner" <tglx@...utronix.de>,
        "Greg Kroah-Hartman" <gregkh@...uxfoundation.org>,
        "linux-input@...r.kernel.org" <linux-input@...r.kernel.org>,
        lkml <linux-kernel@...r.kernel.org>
Subject: Re: Re: [PATCH] Input: omap-keypad - fix runtime pm imbalance on
 error

Fixing this in the PM core will influence all callers of pm_runtime_get_sync().
Therefore I think the better solution is to fix its misused callers.

Regards,
Dinghao

&quot;Dmitry Torokhov&quot; &lt;dmitry.torokhov@...il.com&gt;写道：
> Hi Dinghao,
> 
> On Wed, May 20, 2020 at 6:35 AM Dinghao Liu <dinghao.liu@....edu.cn> wrote:
> >
> > pm_runtime_get_sync() increments the runtime PM usage counter even
> > the call returns an error code. Thus a pairing decrement is needed
> > on the error handling path to keep the counter balanced.
> 
> This is a very surprising behavior and I wonder if this should be
> fixed in the PM core (or the required cleanup steps need to be called
> out in the function description). I also see that a few drivers that
> handle this situation correctly (?) call pm_runtime_put_noidle()
> instead of pm_runtime_put_sync() in the error path.
> 
> Rafael, do you have any guidance here?
> 
> Thanks.
> 
> -- 
> Dmitry